The Process of Wastewater Treatment
The diagram below shows the step-by-step process of treating wastewater in a modern treatment plant. Summarise the information by selecting and reporting the main features, and make comparisons where relevant. *[Diagram Description: A 6-stage flowchart. Stage 1: Inlet works – wastewater enters through screens that remove large solids. Stage 2: Primary settlement – water flows into large tanks where heavier solids settle at the bottom as sludge. Stage 3: Aeration – air is pumped into the water to encourage bacteria to break down organic matter. Stage 4: Secondary settlement – the water is left to settle again; remaining solids form sludge. Stage 5: Tertiary treatment – water passes through sand filters and is disinfected with chlorine or UV light. Stage 6: Discharge – treated water is released into rivers or the sea. Sludge from stages 2 and 4 is sent to a separate process for digestion and disposal.]*